Seeking Advice on Alpair project for living room

I’ve been doing a lot of research the last few days for what my best options are for my new living room remodel. I’ve been absent from speaker building for a number of years so I wasn’t up to speed on what is available these days. If anyone has some advice or suggestions for my room and situation I am all ears.

The living room is approx. 16ft by 20ft. Unfortunately the new speakers will need to reside in a new (to be built) cabinet on the long wall (3ft offset from centre of wall). Cabinet will be 64” wide, 19” deep and extend from floor to the 9ft ceiling. The tv will occupy the cabinet section at 39” to 75” from the floor. Area’s left for speakers is above the 75” height level or an 8 or 9” high section just under the tv section. There will also be a bench area next to the cabinet that will allow for a sub to be built into its base if needed.

Speakers will be used for 2 channel music about 50% of the time and most likely in a 3.1 configuration for movies/TV the rest of the time. Surround may be added at some point but they are not a priority. Speakers will be driven by a Denon S700 HT receiver.

From my recent research I am thinking of building some bookshelf enclosures (sealed vs vented??) for the Alpair 7.3 (or 10.2) drivers to serve as the front and centre channels. I'm also thinking of using a pair of CSS SDX10 sub woofers for filling in the low end and crossing them over around 100 or 120hz. Open to ideas on how best to integrate these two or what better options are available.

I don't think there's a helluva lot to critique about your plan for this set-up.

As much as I enjoyed A7s in the front row of a small room HT rig ( currently driven by an Onkyo receiver) I don't regret upgrading that phalanx to A10Ps, although the metal 10.3s wouldn't be hurtful either.
If you're talking about the AVR S700W, even after de-rating the power specs by at least 25%, you probably have more than enough power for the room described.

The centre channel sits immediately under the 42" screen ( I know, hopelessly small for the 10 ft viewing distance), and the L&R main enclosures place the drivers probably 4" above that enclosure's acoustic centre .

All of those enclosures are vented ( designs by Dave ) - I've not spent significant time listening to any of the 10s in sealed enclosures, so advice on that choice is open to the floor for discussion.

A pair of SDX 10s XO'd about where you're thinking would be a great start - when you run the Audyssey speaker set-up protocol you'll likely find the default finding of lower than 120Hz if you spec the front row speakers as large. In my own case (7.1 with front height and rear surrounds using CHP70 and Alpair 6s respectively) , I manually adjusted the LFE channel XO to 80Hz after running the automated process. I'm using a Dayton AP150 to power my own woofers - soon to be a pair bridged in mono upon return of one from loan.

I'd plan on placing the subs separately - in my case a pair of front wall corners. This certainly works aesthetically, as the room's furnishing layout somewhat constrains placement - they are heard well enough, and not really seen, which makes Mrs B happy - always a optimal compromise.
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Destroyer OS

Paid Member
2005-11-14 11:09 pm
I was wondering about a spiral horn for Alpairs earlier... but if you MUST put them in a cabinet... I'd imagine the 10's would be smart for a little more output on HT. I'm looking at them for just music, actually.

Honestly I prefer large drivers for HT. Not sure what to use in cabinets, but Hawthorn Audio OB drivers with subs are freaking sweet for HT. I gave mine to my father when I moved to a place that I couldn't have them. He's probably not going to give them back!

That said I prefer 2 channel HT with higher quality parts as opposed to trying to make mediocre multi channel. Admittedly a center channel would be nice due to stupid audio mixing by movie people, but it's not necessarily worth it if you can't use a good DAC.
Since this thread is specifically addressed at Alpairs, I'd opine that either version of the 10 hit a sweet spot for both music and "multi-channel", and they certainly require far smaller enclosures and total floorspace than a large scale OB such as the Hawthornes.

For those of us who've long since accepted the constraints of "domestic considerations", such high performance / large footprint systems can be enjoyed in their native environments, just not our own. :eek:

Not all multi-channel audio mixing is stupid, although I think most movies are "calibrated" for large cinemas and don't necessarily translate well to small domestic rooms, and I've found some of the "made for TV" films to be equal in sound quality - if not complexity - to any of the big screen productions.

I watched "Lone Survivor" over the weekend (and still feel the sympathy concussion and broken ribs), and afterwards by accident, I ended up catching the last half hour or so of a recent Michael Bay extravaganza - Transformers, something or other. While the whole thing was as preposterous as only Michael can achieve, I found the sound engineering quite impressive, and almost needed to check the room for shrapnel damage at the end.
Thanks for suggestions chris and Destroyer. Although I have been curious how a large open baffle speaker would compare to my current sets of speakers it just is not going to be an option for this living room build. I also would go with 2 channel for movies but have found you really need the center channel for dialog on some movies.

Based on the your suggestions I am now leaning toward the Alpair 10's. Doing some quick research between the 10P and 10.3M its seems its more a personal taste issue when deciding between them. Chris may I ask what particular enclosures you used for the 10P's. Only DIY plans I see out there are the Golden Ratio Mar-Ken 10p on the Frugalphile site.
Pensils, also on the frugal-phile site.

And if you are willing to pay a token for plans, Bob Brines has an ML-TL, Scott ( has his big Megalith horns, and the complete set of plans from which the CGR Mar-Ken comes is available from planet10-hifi (in excess of 50 pages and growing).

Chris has his A10p in the larger of the compact floorstanders… the smaller compact floorstander has the same alignment as the CGR. And he has a centre that is the same alignment (and size, different shape) as the CGR.

Compact floorstanders and centre for Alpair10P

Pensils for this model would place the driver higher than might easily align with acoustic center of the center enclosure, something I generally try for. Perhaps not readily apparent from the photos, but both enclosure designs have a 5dg slant to the front baffles.


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Bob Brines

2003-01-31 10:11 pm
Nicely done, Bob, and I'd gather an easier build than with the elliptical supra-baffle? I'd be fudgesicled with any of the non-rectilinear designs, were it not for the shop's CNC.:eek:

Pattern routing, Chris. Making the pattern out of 1/4" hardboard was fiddly and time consuming, but after that, it's 5 minutes at the router table to make the part. On BR's I put the port in the subra-baffle: